Intervet Inc. v. Merial Ltd.: Federal Circuit Reverses Noninfringement Declaratory Judgment, Dissent Takes on Gene Patentability

Intervet Inc. v. Merial Ltd., No. 2009-1568 (Fed. Cir. Aug. 4, 2010)

Slip Opinion

On August 4, 2010, the United States Court of Appeals for the Federal Circuit reversed and remanded the declaratory judgment of the United States District Court of the District of Columbia, which held that Intervet’s Porcine Circovirus vaccine (“PCV-2”) did not infringe Merial’s gene patent. The majority reversed the lower court’s ruling on grounds of claim construction and for improper application of the doctrine of equivalents.

Plaintiff Intervet Inc. (“Intervet”) filed a complaint against Merial Limited (“Merial”) in 2006, asking for a declaratory judgment stating that its PCV2 vaccine did not infringe on Merial’s gene patent. The DC District Court granted this declaratory ruling in Intervet’s favor, finding that Merial’s patent covered only the specific DNA sequences disclosed. On appeal, the Federal Circuit rejected the district court’s construction of Merial’s patent claim as overly limiting, finding that Merial had a proper claim directed at the entire genus of PCV2 sequences. The Federal Circuit also held that a narrowing amendment to the claim did not estop Merial from asserting that one or more elements of Intervet’s product were equivalent to the elements in the claim. Dissenting in part, Circuit Judge Dyk argued that mere isolation of a DNA molecule is not sufficient for patentability.

Patently-O and The Patent Prospector provide an overview of the decision. Inventive Step discusses and questions the appropriateness of Judge Dyk’s dissenting opinion.

Merial’s patent application defined the invention by listing five genetic sequences of the isolated DNA molecule of PCV2 and a vector containing the DNA.  Merial’s patent contained no indication that other sequences were also part of the invention. The district court therefore construed Merial’s patent claim to be limited to those five sequences. The Federal Circuit disagreed, noting that “[s]equences are representative of the scope of broader genus claims if they indicate that the patentee has invented species sufficient to constitute the genera” (citing Enzo Biochem, Inc. v. GenProbe, Inc., 323 F.3d 956, 697 (Fed. Cir. 2002); In re Smythe, 480 F.2d 1376, 1383 (C.C.P.A. 1973). The court held that Merial, by disclosing five PVC2 species and providing a PCV1 counterexample that does not fall under the claim, had properly defined the scope of the claimed PVC2 genus.

The court of appeals also found problems with the district court’s application of prosecution history estoppel under the doctrine of equivalents. The doctrine of equivalents allows a finding of infringement where one or more elements of the accused product are equivalent to elements in the patent claim. However, if during patent prosecution, a claim is narrowed by an amendment for a substantial reason related to patentability, the patentee may be estopped from using the doctrine of equivalents. See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 740 (2002). The district court determined that an amendment to one of Merial’s patent claims directed to a group of open reading frames (“ORFs”) estopped Merial from asserting that its claims cover a non-claimed PCV2 ORF as an equivalent. While the Federal Circuit agreed that the purpose of the narrowing amendment was substantially related to patentability, it held that the amendment “bore only a tangential relation to the question of which DNA sequences are and are not properly characterized as PCV2.” Therefore, the court concluded that prosecution history estoppel did not prevent Mariel from asserting its claim under the doctrine of equivalents.

Judge Dyk dissented in part and wrote separately to offer his opinion on the patentability of isolated DNA under 35 U.S.C. § 101. This is an issue that neither the Federal Circuit nor the Supreme Court has directly addressed and that neither the district court nor the parties in this case raised. Judge Dyk expressed concern with one of Merial’s claims that was “not limited to use of a particular isolated DNA molecule in a vaccine or other application” but that offered patent protection to an isolated DNA molecule itself. Citing the recent Bilski decision, Judge Dyk argued that “allowing the patenting of naturally occurring substances” like DNA would “preempt the use by others of substances that should be freely available to the public.” This indication by Judge Dyk that he does not consider isolated DNA patentable is significant in light of Assn. for Molecular Pathology v. USPTO. The district court in that case invalidated two isolated gene patents for similar reasons, and the case is in the process of appeal to the Federal Circuit.

Chinh Vo is a 2L at the Harvard Law School.